Create a sequence

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the full burden and does so well: it explains delayHours semantics, reply routing to the sender, the requirement that links stay on the sender's own domain, and what the response returns. It omits permission/auth requirements and any rate-limit behavior, keeping it short of a 5.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is three tightly packed sentences that lead with the core action before layering in step semantics and constraints. No filler, though the density of rules makes it slightly list-like.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a 3-parameter mutation tool with no annotations and no output schema, the description covers parameter intent, key constraints, and return values adequately. It could say more about validation limits (max 10 steps) or auth, but an agent has enough to invoke it correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is only 33%, so the description must compensate, and it does: it clarifies delayHours (first from enrollment, later from previous step), the sender format expectation, and that text/html support {{variable}} placeholders. This adds real meaning beyond the bare schema, though not every parameter is touched.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description opens with a specific verb and resource ('Create a multi-step email sequence'), so the agent immediately knows the operation. It doesn't explicitly contrast itself with siblings like sequence_status, enroll_leads, or stop_enrollment, so it falls just short of the top score.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

There is no explicit when-to-use guidance and no named alternative among the sibling tools (e.g., enroll_leads or sequence_status). Some prerequisite context is implied by 'from a sender on your Resend domains,' but the agent must infer when this tool is the right choice.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.